Project 1. Auditory and Visual Sensory Processing The goal of the Program Project is to study hierarchical leyels of neural processing and cognition in order to identify the neural and functional underpinnings of cognitive deficits in children (ages 7-10) with several neurodevelopmental disorders - Specific Language Impairment (LI), Early Unilateral Focal Brain Lesions (FL), High Functioning Autism (HFA), and Williams Syndrome (WS). Within this framework, the role of Project 1 is to systematically characterize the neural functioning of the sensory/perceptual mechanisms across two modalities, auditory and visual, including three core processing aspects (time, space, features) and three processing levels (bottom-up driven, cortical sensory, top-down driven) in each modality. Our three overarching goals are (1) to determine the unique population landscapes of the sensory/perceptual deficits across the modalities, levels, and aspects;(2) map these impairment profiles onto the hierarchy of higher cognitive functions of attention, language, and social skills, and (3) onto the neuro-anantomic and white matter connectivity measures. Over the past 15 years of research we have identified a number of sensory problems in these clinical populations, however the extent of these abnormalities across the modalities and processing levels, or their impact onto the cognitive functions remains unclear. Exactly these questions will be addressed by the carefully matched experimental measures proposed herein. Corresponding to the three overarching goals, three sets of competing or complimentary hypotheses will be tested, addressing alternative mechanisms of neurodevelopmental damage and compensatory plasticity, logistics of hierarchical information processing, and neural structure-function relationships. Behavioral tasks, continuous electrophysiological brain activity and event-related brain potentials will be assessed using modern data acquisition and analytic approaches. These measures will sample the very foundations of human cognition. Their deficits will be traced across processing aspects, leyels, modalities, to the higherlevel cognitive impairment profiles, and mapped onto the corresponding brain volumetric (MRI) and white matter integrity measures (DTI). In sum, this approach will yield a systematic and integrated view into the sensory/perceptual functioning and its neural bases in the Center clinical populations. Through the integration across the Projects, we will be able to trace the ramifications of these abnormalities onto the higher-order cognitive disability profiles. This will provide new and fuller insights into the neuro-pathpgenic mechanisms of these developmental disorders that may lead to the earlier and more specific diagnostic and intervention strategies.